Outer membrane vesicles (OMV) are sphere-like nanoscale particles spontaneously shed by gram-negative bacteria. OMV produced from certain bacterial strains are genotoxic to mammalian cells, although, the exact mechanism by which this OMV exert its toxic effect is unknown. The pks island is an arrangement of genes which encodes for the biosynthesis of a genotoxic compound likewise. We are interested in exploring the correlation in the presences of the pks island and the possibility of playing a role in the formation of outer membrane vesicles (OMV). We report the lipid composition of OMV from selected clinical isolates of Escherichia coli that contain the pks island genes and compare them with OMV extracted from an isogenic mutant and strain lacking the pks island determined by GC/MS. As preliminary results, we observe a significant difference in the lipid composition of the IHE3034 (pks+ strain) OMV and the IHE3034-ΔclbP OMV. clbP gene is presumed to be involved in pks island natural product biosynthesis. We conclude that the deletion of clbP peptidase causes a decrease in the percentage of 12:0 fatty acids, an increase of 16:0 fatty acids and the production of other fatty acids not present in OMV from the wild type strain IHE3034. These results suggest that the pks island plays a role in the composition of the bacterial outer membrane, establishing a possible correlation between pks island toxic effects and the secretion of OMV produced.

Fatty acids analysis of outer membrane vesicles from Escherichia coli harboring the pks island

254th National Meeting (2017)

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